org.gradle.playframework.util

Class CollectionUtils

java.lang.Object

org.gradle.playframework.util.CollectionUtils

public final class CollectionUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CollectionUtils.SetDiff<T> The result of diffing two sets.

Method Summary

Modifier and Type	Method and Description
static <R,I,C extends Collection<R>> C	collect(Iterable<? extends I> source, C destination, org.gradle.api.Transformer<? extends R,? super I> transformer)
static <R,I> List<R>	collect(Iterable<? extends I> source, org.gradle.api.Transformer<? extends R,? super I> transformer)
static <K,V> Map<K,V>	collectMap(Iterable<? extends V> items, org.gradle.api.Transformer<? extends K,? super V> keyGenerator) Given a set of values, derive a set of keys and return a map
static <K,V> void	collectMap(Map<K,V> destination, Iterable<? extends V> items, org.gradle.api.Transformer<? extends K,? super V> keyGenerator) Given a set of values, derive a set of keys and populate a map.
static <T> CollectionUtils.SetDiff<T>	diffSetsBy(Set<? extends T> left, Set<? extends T> right, org.gradle.api.Transformer<?,T> compareBy) Provides a “diff report” of how the two sets are similar and how they are different, comparing the entries by some aspect.
static <T> T	findFirst(Iterable<? extends T> source, org.gradle.api.specs.Spec<? super T> filter)
static <T> List<T>	flattenCollections(Class<T> type, Object... things) Recursively unpacks all the given things into a flat list, ensuring they are of a certain type.
static List<?>	flattenCollections(Object... things) Recursively unpacks all the given things into a flat list.
static <T> Set<T>	toSet(Iterable<? extends T> things)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

findFirst

@Nullable
public static <T> T findFirst(Iterable<? extends T> source,
                                        org.gradle.api.specs.Spec<? super T> filter)

collect

public static <R,I> List<R> collect(Iterable<? extends I> source,
                                    org.gradle.api.Transformer<? extends R,? super I> transformer)

collect

public static <R,I,C extends Collection<R>> C collect(Iterable<? extends I> source,
                                                      C destination,
                                                      org.gradle.api.Transformer<? extends R,? super I> transformer)

flattenCollections

public static List<?> flattenCollections(Object... things)

Recursively unpacks all the given things into a flat list. Nulls are not removed, they are left intact.

Parameters:

things - The things to flatten

Returns:

A flattened list of the given things

flattenCollections

public static <T> List<T> flattenCollections(Class<T> type,
                                             Object... things)

Recursively unpacks all the given things into a flat list, ensuring they are of a certain type. Nulls are not removed, they are left intact. If a non null object cannot be cast to the target type, a ClassCastException will be thrown.

Type Parameters:

T - The target type in the flattened list

Parameters:

type - Class token for the target type <T> in the flattened list

things - The things to flatten

Returns:

A flattened list of the given things

toSet

public static <T> Set<T> toSet(Iterable<? extends T> things)

collectMap

public static <K,V> void collectMap(Map<K,V> destination,
                                    Iterable<? extends V> items,
                                    org.gradle.api.Transformer<? extends K,? super V> keyGenerator)

Given a set of values, derive a set of keys and populate a map.

Type Parameters:

K - The type of the keys

V - The type of the values

Parameters:

destination - The map to populate

items - The values to derive keys from

keyGenerator - The function to derive keys from the values

collectMap

public static <K,V> Map<K,V> collectMap(Iterable<? extends V> items,
                                        org.gradle.api.Transformer<? extends K,? super V> keyGenerator)

Given a set of values, derive a set of keys and return a map

Type Parameters:

K - The type of the keys

V - The type of the values

Parameters:

items - The values to derive keys from

keyGenerator - The function to derive keys from the values

Returns:

The resulting map of keys to values

diffSetsBy

public static <T> CollectionUtils.SetDiff<T> diffSetsBy(Set<? extends T> left,
                                                        Set<? extends T> right,
                                                        org.gradle.api.Transformer<?,T> compareBy)

Provides a “diff report” of how the two sets are similar and how they are different, comparing the entries by some aspect. The transformer is used to generate the value to use to compare the entries by. That is, the entries are not compared by equals by an attribute or characteristic. The transformer is expected to produce a unique value for each entry in a single set. Behaviour is undefined if this condition is not met.

Type Parameters:

T - The type of the entry objects

Parameters:

left - The set on the “left” side of the comparison.

right - The set on the “right” side of the comparison.

compareBy - Provides the value to compare entries from either side by

Returns:

A representation of the difference